Method and apparatus for identifying lead-related conditions using prediction and detection criteria

Abstract

A method for delivering therapy in a medical device that includes a two-tiered approach of determining the presence of a lead-related condition, and determining, in response to a lead-related condition being present, the presence of oversensing. Deliver of therapy by the medical device is controlled in response to determining that both the lead-related condition and oversensing are present.

1. A method for delivering therapy in a medical device, comprising:
 determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition; 
 determining, in response to a lead-related condition being present, the presence of oversensing; and 
 
     controlling delivery of therapy in response to the lead-related condition and oversensing being present, wherein determining the presence of a lead-related condition comprises:
 determining whether a first oversensing criteria is satisfied; 
 determining whether a second oversensing criteria is satisfied; 
 determining whether an impedance criteria has been satisfied; and 
 generating an alert in response to more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied, wherein determining whether a first oversensing criteria is satisfied comprises: 
 determining whether a predetermined number of RR-intervals are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and 
 determining whether the predetermined number of RR-intervals occur within a second predetermined time period. 
 
   
   
     2. The method of  claim 1 , wherein determining whether a second oversensing criteria is satisfied comprises determining whether there are a predetermined number of events having average cycle lengths that are less than a predetermined threshold occurring within a predetermined time period. 
   
   
     3. The method of  claim 1 , wherein determining whether an impedance criteria has been satisfied comprises:
 measuring a lead impedance; 
 determining a short-term impedance trend; 
 determining a long-term impedance trend; and 
 applying a set of diagnostic criteria to the short-term and long-term impedance trends. 
 
   
   
     4. A method for delivering therapy in a medical device, comprising:
 determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition; 
 determining, in response to a lead-related condition being present, the presence of oversensing; and 
 
     controlling delivery of therapy in response to the lead-related condition and oversensing being present, wherein determining the presence of a lead-related condition comprises:
 determining whether a first oversensing criteria is satisfied; 
 determining whether a second oversensing criteria is satisfied; 
 determining whether an impedance criteria has been satisfied; and 
 generating an alert in response to more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied, wherein determining whether a first oversensing criteria is satisfied comprises: 
 determining a number of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and 
 determining whether the number of RR-intervals within the first predetermined time period is greater than a predetermined threshold. 
 
   
   
     5. A method for delivering therapy in a medical device, comprising:
 determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition; 
 determining, in response to a lead-related condition being present, the presence of oversensing; and 
 
     controlling delivery of therapy in response to the lead-related condition and oversensing being present, wherein determining the presence of a lead-related condition comprises:
 determining whether a first oversensing criteria is satisfied; 
 determining whether a second oversensing criteria is satisfied; 
 determining whether an impedance criteria has been satisfied; and 
 generating an alert in response to more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied, wherein determining whether a first oversensing criteria is satisfied comprises: 
 determining whether a time duration window is greater than a threshold time period; and 
 determining, in response to the time duration window not being greater than the threshold time period, a ratio of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device. 
 
   
   
     6. A method for delivering therapy in a medical device, comprising:
 determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition; 
 determining, in response to a lead-related condition being present, the presence of oversensing; and 
 
     controlling delivery of therapy in response to the lead-related condition and oversensing being present, wherein determining the presence of a lead-related condition comprises:
 determining whether a first oversensing criteria is satisfied; 
 determining whether a second oversensing criteria is satisfied; 
 determining whether an impedance criteria has been satisfied; and 
 generating an alert in response to more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied, wherein determining whether a first oversensing criteria is satisfied comprises: 
 determining, during a first time period, whether a predetermined number of RR-intervals are within a second predetermined time period subsequent to a blanking period associated with a sensing device; 
 determining, during a third time period subsequent to the first time period, a ratio of RR-intervals that are within the second predetermined time period subsequent; and 
 determining, during a fourth time period subsequent to the second time period, whether the number of RR-intervals within the second predetermined time period is greater than a predetermined threshold. 
 
   
   
     7. A method for delivering therapy in a medical device, comprising:
 determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition; 
 determining, in response to a lead-related condition being present, the presence of oversensing; and 
 
     controlling delivery of therapy in response to the lead-related condition and oversensing being present, wherein determining, in response to a lead-related condition being present, the presence of oversensing comprises:
 sensing cardiac signals and detecting cardiac events via a first electrode configuration; 
 determining the presence of an episode event in response to the detected cardiac events; 
 sensing the cardiac signals via a second electrode configuration; 
 determining predetermined values associated with cardiac signals sensed via the second electrode configuration corresponding to the event episode; and 
 controlling delivery of therapy in response to the determined values. 
 
   
   
     8. The method of  claim 7 , wherein determining predetermined values comprises:
 determining voltage values of a predetermined number of samples located within a window defined about the cardiac signals sensed via the second electrode configuration; 
 determining a sample maximum voltage value and a sample minimum voltage value corresponding to the predetermined number of samples; and 
 comparing the sample maximum voltage value and the sample minimum voltage value to generate sample amplitudes. 
 
   
   
     9. The method of  claim 8 , wherein controlling delivery of therapy comprises:
 determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; 
 determining whether the maximum amplitude is greater than a maximum amplitude threshold and the minimum amplitude is less than a first minimum amplitude threshold; and 
 determining whether the minimum amplitude is less than a second minimum amplitude threshold. 
 
   
   
     10. The method of  claim 8 , wherein controlling delivery of therapy comprises:
 determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; and 
 comparing the maximum amplitude and the minimum amplitude. 
 
   
   
     11. A method for delivering therapy in a medical device, comprising:
 determining, prior to determining the presence of an episode event, whether a first oversensing criteria, a second oversensing criteria, and an impedance criteria has been satisfied; 
 generating an alert in response to more than one of the first oversensing criteria, the second over sensing criteria and the impedance criteria being satisfied; 
 sensing cardiac signals and detecting cardiac events via a first electrode configuration in response to more than one of the first oversensing criteria, the second over sensing criteria and the impedance criteria being satisfied; 
 determining the presence of an episode event in response to the detected cardiac events; 
 sensing the cardiac signals via a second electrode configuration; 
 determining predetermined values associated with cardiac signals sensed via the second electrode configuration corresponding to the event episode; and 
 controlling delivery of therapy in response to the determined values. 
 
   
   
     12. The method of  claim 11 , wherein determining whether a first oversensing criteria is satisfied comprises:
 determining whether a predetermined number of RR-intervals are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and 
 determining whether the predetermined number of RR-intervals occur within a second predetermined time period. 
 
   
   
     13. The method of  claim 11 , wherein determining whether a first oversensing criteria is satisfied comprises:
 determining a number of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and 
 determining whether the number of RR-intervals within the first predetermined time period is greater than a predetermined threshold. 
 
   
   
     14. The method of  claim 11 , wherein determining whether a first oversensing criteria is satisfied comprises:
 determining whether a time duration window is greater than a threshold time period; and 
 determining, in response to the time duration window not being greater than the threshold time period, a ratio of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device. 
 
   
   
     15. The method of  claim 11 , wherein determining whether a second oversensing criteria is satisfied comprises determining whether there are a predetermined number of events having average cycle lengths that are less than a predetermined threshold occurring within a predetermined time period. 
   
   
     16. The method of  claim 11 , wherein determining whether an impedance criteria has been satisfied comprises:
 measuring a lead impedance; 
 determining a short-term impedance trend; 
 determining a long-term impedance trend; and 
 applying a set of diagnostic criteria to the short-term and long-term impedance trends. 
 
   
   
     17. The method of  claim 11 , wherein determining whether a first oversensing criteria is satisfied comprises:
 determining, during a first time period, whether a predetermined number of RR-intervals are within a second predetermined time period subsequent to a blanking period associated with a sensing device; 
 determining, during a third time period subsequent to the first time period, a ratio of RR-intervals that are within the second predetermined time period subsequent; and 
 determining, during a fourth time period subsequent to the second time period, whether the number of RR-intervals within the second predetermined time period is greater than a predetermined threshold. 
 
   
   
     18. The method of  claim 11 , wherein determining predetermined values comprises:
 determining voltage values of a predetermined number of samples located within a window defined about the cardiac signals sensed via the second electrode configuration; 
 determining a sample maximum voltage value and a sample minimum voltage value corresponding to the predetermined number of samples; and 
 comparing the sample maximum voltage value and the sample minimum voltage value to generate sample amplitudes. 
 
   
   
     19. The method of  claim 18 , wherein controlling delivery of therapy comprises:
 determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; 
 determining whether the maximum amplitude is greater than a maximum amplitude threshold and the minimum amplitude is less than a first minimum amplitude threshold; and 
 determining whether the minimum amplitude is less than a second minimum amplitude threshold. 
 
   
   
     20. The method of  claim 18 , wherein controlling delivery of therapy comprises:
 determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; and 
 comparing the maximum amplitude and the minimum amplitude.